Scanning device

ABSTRACT

A scanning device for scanning an original which is set at a predetermined position and has information recorded thereon comprises: a plurality of light emission members for emitting lights of different wavelengths from each other; a first reflection member having a plurality of reflection planes for selectively reflecting emitted lights of a plurality of wavelengths coming from the light emission members and an optical aid portion; a second reflection member for reflecting the lights reflected by the first reflection member to focus them on the original in a linear pattern; and an imaging optical system for focusing the lights of the linear pattern onto a sensor, whereby the sensor receives the information of the original. The device has depressions arranged around the light emission members for reflecting lights and the depressions are shaped differently depending on increased wavelengths of the light emissions of the corresponding light emission members so that the light intensities of the respective wavelengths of light emissions and decreased non-uniformity of the light intensity are attained.

This is a continuation of application Ser. No. 08/339,217 filed Nov. 10,1994, now abandoned, which is a division of application Ser. No.08/070,801 filed Jun. 3, 1993 (now U.S. Pat. No. 5,420,712).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a scanning device for scanning an imagerecorded on a film.

2. Related Background Art

In order to read a recorded color image, each of the red, green and blueimages must be read. In order to reduce a size of this type of device,it has been proposed to use a plurality of LED's for red, green and blueas illumination sources. However, because the presently available LEDhas a big difference in intensity depending on the color of lightemission, the number of LED's used is varied depending on the color oflight emission.

Since the light intensity of the LED is very small depending on thecolor of light emission and the number of LED's used is limited in orderto reduce the size of the device, it is necessary to efficiently operatethe LED's.

Further, since a limited number of LED's are used depending on the colorof light emission, non-uniformity of illumination occurs. Accordingly,it is necessary to eliminate a component of a light source whichadversely affects the image quality.

SUMMARY OF THE INVENTION

The scanning device of the present invention scans an original which isset at a predetermined position and has information recorded thereon.The present scanning device comprises: a plurality of light emissionmembers for emitting lights of different wavelengths from each other; afirst reflection member having a plurality of reflection planes forselectively reflecting lights of a plurality of wavelengths coming fromby the light emission members and optical aid means, a second reflectionmember for reflecting the light reflected by the first reflection memberto focus it on the original in a linear pattern; and focusing means (animaging optical system) for focusing the information of the originalonto a sensor in accordance with the reflected light from the secondreflection member.

The device has depressions arranged around the light emission membersfor reflecting lights and the depressions are shaped differentlydepending on the wavelengths of the light emissions of the correspondinglight emission members so that increased light intensities of therespective wavelengths of light emissions and the decrease ofnon-uniformity of the light intensity are attained.

In the present device, the light intensity on the original increaseswhen optical distances from the respective light emission members to theoriginal are equal.

In the present device, the position adjustment of the sensor isfacilitated by arranging the original slightly off the focal point ofthe light focused by the second reflection member so that thenon-uniformity of the light intensity of the light illuminating theoriginal is reduced.

In the present device, when the focusing means is a lens and the lightprojected by the second reflection member is converged such that theinformation light from the original does not fill an aperture of thelens, flare is prevented and a high contrast image is produced.

In the present device, infrared light which adversely affectsperformance may be eliminated by reflecting only a visible light or alight of only a waveform necessary for scanning.

In the present device, the light intensity on a center axis of a line ofa plurality of light emission members is increased by arranging thelight emission members in a line and arranging them such that a maximumlight intensity of the light emission members is arranged around thecenter axis of the line.

In the present device, the leakage of the reflected light is preventedby providing focusing means for focusing the reflected light from thefirst reflection member to the second reflection member.

In the present device, a high efficiency is attained by arranging thelight emission members in a line and arranging the light emissionmembers such that a maximum light intensity of the light emissionmembers is arranged around the center axis of the line. Where LED's ofgenerally square shape are used as the light emission members, it ispreferable that the LED's are arranged such that one side of the squareis inclined from the axis of the line by approximately 30 degrees.

In another aspect, the present invention relates to a light projectiondevice for a scanning device for scanning an original having informationrecorded thereon. The device comprises a plurality of light emissionmembers for emitting lights of different wavelengths from each other,and optical aid means arranged around the light emission members forfocusing the lights of different wavelengths emitted by the plurality oflight emission members. The light emission members are arranged in aline and also arranged such that a maximum light intensity of the lightemission members is arranged around the center axis of the line. Theoptical aid means have different shapes depending on the wavelengths ofthe lights emitted by the corresponding light emission members. Wherethe LED's of generally square shape are used as the light emissionmembers, the LED's are arranged such that one side of the square isinclined from the axis of the line by approximately 30 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a device for forming an image in one embodiment of thepresent invention;

FIGS. 2A and 2B show detail of a light source 601 in FIG. 1; and

FIG. 3 shows a line arrangement of LED chips and a light emission member301 of the LED chip and a depressions 302 and 303.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a device for forming an image in one embodiment of thepresent invention.

In FIG. 1, the device comprises a light source 601, a concave mirror611, a mirror 620, a mirror 621, an image forming lens 631 and a sensor641.

The light source 601 uses LED chips of three colors as a light emissionsource.

The concave mirror 611 is of toroidal design, that is, it is a mirrorhaving curvatures of two different axes for linearly focusing the lightfrom the light source 601 onto a plane of a film 622.

The mirror 620 reflects the light reflected by the concave mirror 611 todirect it to the plane of the film 622.

The mirror 621 reflects the light transmitted through the film 622 tothe image forming lens 631.

The image forming lens 631 focuses the reflected light from the mirror621 onto the sensor 641.

The sensor 641 is a CCD which converts the light focused by the imageforming lens 631 to an electrical signal.

The film 622 may be a negative film or a positive film having lighttransparency.

FIGS. 2A and 2B show detail of the light source 601 of FIG. 1.

In FIGS. 2A and 2B, the light source 601 comprises two red LED chips,four green LED chips, six blue LED chips, a support table 650, adichroic mirror 660, an infrared blocking filter 661, a common lead 670,a blue lead 671, a red-green lead 672 and an insulator 680.

The red LED chip uses GaAlAs (gallium aluminum arsenide) as a materialand has a cathode electrode on a top light emission plane and an anodeelectrode on a bottom surface. The green LED chip uses GaP/GaP (galliumphosphor/gallium phosphor) as a material and has an anode electrode on atop light emission plane and a cathode electrode on a bottom plane. Theblue LED chip uses SiC (silicon carbide) as a material and has an anodeelectrode on a top light emission plane and a cathode electrode on abottom plane. They generate lights of red, green and blue, respectively.

Six LED chips are arranged on the support table 650 in two lines,namely, the red LED chips and the green LED chips in one line and theblue LED chips in one line. In the line of the red and green LED chips,they are arranged in the order of green, red, green, green, red andgreen. They are arranged by taking the non-uniformity of illuminationdue to the difference in numbers into consideration, although thepresent invention is not limited thereto and further improvement may beattained by changing the distances between the LED chips.

The numbers of LED chips of different colors used are different becauseof a substantial difference between light emission intensities per chipof the presently available LED chips of various colors. However, sincethe illumination light intensity may not be made uniform by merelychanging the numbers of chips, the light emission times of the LED chipsof the respective colors may be adjusted when the image is read.

The respective LED chips are arranged such that the optical distancesfrom the light emission surfaces of the respective LED chips to the exitplanes are equal. As a result, the lights of all colors are focused onthe film 622.

The support table 650 is made of a conductive material.

The common lead 670 is electrically connected to the support table 650and the blue lead 671 and the red-green lead 672 are insulated from thesupport table 650.

The common lead 670 is connected to the anodes of the red LED chips, thecathodes of the green LED chips and the cathodes of the blue LED chipsthrough the support table 650.

The blue lead 671 is insulated from the support table 650 by aninsulator 680, and wire-bonded to the anodes of the blue LED chips.

The red-green lead 672 is insulated from the support table by theinsulator 680 and wire-bonded to the cathodes of the red LED chips andthe anodes of the green LED chips.

It is necessary to arrange the red LED chips and the green LED chipswhich use the common lead, in the opposite polarities so that the red,green and blue LED chips can independently emit lights. Since the redLED chip and the green LED chip used in the present embodiment are ofopposite polarities as described above, a vertical arrangement for allLED chips may be used.

The dichroic mirror 660 comprises a dichroic plane 666 and an aluminumplane 667 coated by an aluminum layer. The blue light emitted from theblue LED chip is reflected by the dichroic plane 666, and the red andgreen lights emitted from the red and green LED chips pass through thedichroic plane 666 and are reflected by the aluminum plane 667. Thosereflected lights pass through the same light path on an exit plane.

The blue LED chip which uses SiC as the material emits not only the bluelight but also a small quantity of green light. Since a blue reflectionfilm for selectively reflecting only the blue light is applied to thedichroic plane 666 of the dichroic mirror 660, the green light from theblue LED chip is not reflected. However, the aluminum plane 667 reflectsthe green light emitted by the blue LED chip. This will deteriorate theimage quality. Thus, the dichroic mirror 660 is arranged in such amanner that a strong light around the axis of the line of the blue LEDchips is reflected by the aluminum plane 667 and does not go out of theexit plane. A weak light which goes out of the exit plane is weak byitself and defocused on the film 622 so that it does not significantlyaffect the image quality.

The infrared blocking filter 661 is provided on the exit plane of thelight source 601 and it prevents the degradation of the image quality bythe infrared component included in the red LED light. The infraredblocking filter 661 is not necessary when the aluminum plane 667 of thedichroic mirror 660 is a reflection plane which reflects only a visiblelight. The color reproducibility may be improved by forming a reflectionfilm which reflects only a desired wavelength.

Where the exit plane of the light source 601 is cylindrical or toroidal,the illumination light is focused and a larger amount of light may bereflected from the concave mirror 611.

The dichroic mirror 660, the LED chips and the infrared blocking filter661 are integrally assembled by epoxy which is an optical material.

FIG. 3 shows a line arrangement of the LED chips and the light emissionportion 301 of the LED chip and the depressions 302 and 303.

In FIG. 3, each of the LED chips has the light emission portion 301 ofgenerally square shape when viewed from the top and is arranged suchthat the light emission portion 301 of the LED chip is inclined aroundthe center thereof to the line axis by about 30 degrees.

Since the LED chip has a property of emitting strong lights from fourcorners of the square, it is arranged such that the four corners are notaway from the center axis of the line to increase the light intensityaround the center axis of the LED chips.

The depressions 302 and 303 have silver plating or rhodium or goldplating applied to the surfaces thereof to efficiently direct the lightsfrom the LED chips. Since the number and the shape of the LED chips, theposition of the light emission portion 301 and the transparency of thechip varies from color to color, the height, the inclination angle andthe curvature of the slope are different. The spread of undesired lightcan be suppressed by forming the slope as elliptic or parabolic.

When the depression 302 is elliptic having a major axis along the lineaxis of the LED chips when viewed from the top, the light intensityaround the axis of the LED chip line is increased.

The non-uniformity of the illumination can be reduced for the red LEDchips which are used in a small number by increasing the major axis ofthe ellipse of the depression 302.

A light path is briefly explained by referring to FIG. 1.

The light source 601 emits one of the red, green and blue lights.

The light is reflected by the concave mirror 611 and the mirror 620 anda light focused in line pattern is irradiated to the plane of the film622. A maximum light intensity is attained by focusing onto the film622.

The light transmitted through the film 622 is reflected by the mirror621 and directed to the image forming lens 631.

If the illumination light totally illuminates a lens, flare may takeplace. In order to attain an image of a higher contrast, theillumination light is converged so as to fill 70 percent of the lensaperture. This may be attained by spacing the optical distance of theimage forming lens 631 from the film 622.

The line image formed by the image forming lens 631 on the sensor 641 isconverted to an electrical signal by the sensor 641.

The red, green and blue lights are illuminated to one line of the film622 and the film 622 is moved to the next read line along the X axis bya drive unit, not shown, and the same process is repeated for that line.

A plurality of line information supplied from the sensor 641 areprocessed by a control unit, not shown, and supplied to a monitor.

A second embodiment of the present invention is now explained.

In the present embodiment, the optical distance from the light source601 to the film 622 is slightly shifted.

As a result, the light is not focused on the plane of the film 622 sothat the line illumination light on the film 622 has a width (which isless than 1 mm in order not to decrease the illumination light intensitymore than required) and the line image formed on the sensor 641 also hasa width.

As a result, the positioning for focusing on the sensor 641 isfacilitated. Further, fine positioning of the film 622 is not necessary.Further, since the illumination light is defocused, the non-uniformityof the illumination is reduced.

In a third embodiment of the present invention, the red LED chips whichare used in a small number in the first embodiment are arranged slightlycloser to the dichroic mirror 660. As a result, the red light is notfocused on the film 622 and the line red illumination light on the film622 has a width so that the line image formed on the sensor 641 also hasa width.

As a result, the positioning of the sensor 641 is facilitated by usingthe red light. Further, since the defocusing reduces the non-uniformityof the illumination, it is preferable to shift the red LED chips whichare small in number and have a relatively large non-uniformity of theillumination.

While the red LED chips are arranged to be slightly closer to thedichroic mirror 660 in order to defocus the light in the presentembodiment, they may be arranged further therefrom to obtain thedefocusing. However, they are arranged to be closer in the presentembodiment in order to prevent the light intensity from being reduced.

Since the light intensity decreases when the light is defocused, thepositions of the LED chips which have high illumination light intensitymay be shifted. In the present embodiment, the red LED chips correspondto such LED chips.

In the above embodiments, the light is transmitted through the recordingmedium such as the film. Alternatively, the present invention isapplicable to a device which reflects the information of the recordingmedium to read it.

Since the optical aid means is provided in the present invention, thelight from the light emission member can efficiently directed.

By making the optical distances from the light emission members to therecording medium equal, the light intensity on the recording memberincreases.

By focusing the light slightly off the recording medium, the positioningof the sensor is facilitated and the non-uniformity of the lightintensity of the light illuminating the recording medium is eliminated.

By converging the light such that the lens aperture is not filled, flareis prevented and a light image of a high contrast is attained.

By providing the reflective depressions which are different depending onthe wavelength of the light emission are provided, the light intensitiesare increased and the non-uniformity of the light intensity is reducedfor the respective wavelengths of light emission.

By providing a first reflection member that reflects only the visiblelight or a light of only a desired wavelength, no adverse affect to theinformation is produced and the infrared ray is not reflected.

By disposing the LED chips so that they are inclined approximately 30degrees to arrange the four corners around the center axis in order tobring the maximum light emission portion of the light emission memberaround the center axis of the light emission member, the light intensityon the center axis of the line increases.

By providing focusing means for focusing the reflected light from thefirst reflection member to the second reflection member, the leakage ofthe reflected light is prevented.

What is claimed is:
 1. A light source device for a scanner whichilluminates an original to read an image of the original, said lightsource device comprising:a plurality of light emission members mountedon a base for emitting respective lights of different wavelengths fromeach other; a dichroic mirror mounted on said base and having a dichroicplane and a reflection plane disposed such that light of one of saidwavelengths is reflected by said dichroic plane and light of another ofsaid wavelengths is transmitted by said dichroic plane and reflected bysaid reflection plane back through said dichroic plane so as to leavethe dichroic mirror with a same axis as the light of said onewavelength; and an infrared blocking portion mounted on said base toexclude infrared rays from the light leaving said dichroic mirror.
 2. Alight source device according to claim 1, wherein said infrared blockingportion comprises a surface that does not reflect infrared light andthat is provided at one of said planes of said dichroic mirror.
 3. Alight source device according to claim 1, wherein said infrared blockingportion comprises an infrared blocking filter disposed in front of saiddichroic plane of said dichroic mirror.
 4. A light source deviceaccording to claim 3, wherein said dichroic mirror is disposed with apredetermined inclination relative to a surface of said base, and saidinfrared blocking filter has a surface arranged substantially at a rightangle to said surface of said base.
 5. A light source device for ascanner which illuminates an original to read an image of the original,said light source device comprising:a plurality of first light emittingmembers linearly arranged on a base and which emit light of a firstwavelength; a plurality of second light emitting members linearlyarranged on said base substantially parallel to said first lightemitting members and which emit light of at least a second wavelengthdifferent from said first wavelength; a dichroic mirror mounted on saidbase and having a dichroic plane and a reflection plane disposed suchthat the light of said first wavelength is reflected by said dichroicplane and the light of said second wavelength is transmitted by saiddichroic plane and reflected by said reflection plane back through saiddichroic plane so as to leave said dichroic mirror with a same axis asthe light of said first wavelength; and an infrared blocking portionmounted on said base to exclude infrared rays from the light leavingsaid dichroic mirror.
 6. A light source device according to claim 5,wherein said second light emitting members include light emittingmembers which emit light of a third wavelength different from said firstand second wavelengths, and the light of said third wavelength istransmitted by said dichroic plane and reflected by said reflectionplane back through said dichroic plane so as to leave said dichroicmirror with a same axis as the light of said first wavelength and thelight of said second wavelength.
 7. A light source device according toclaim 5, wherein said infrared blocking portion comprises a surface thatdoes not reflect infrared light and that is provided at said dichroicplane of said dichroic mirror.
 8. A light source device according toclaim 5, wherein said infrared blocking portion comprises an infraredblocking filter disposed in front of said dichroic plane of said firstreflection member.
 9. A light source device according to claim 5,wherein said dichroic mirror is disposed with a predeterminedinclination relative to a surface of said base, and said infraredblocking portion includes an infrared blocking filter disposed on saidbase and having a surface substantially at a right angle to said surfaceof said base.